1. Field of the Invention
The present invention relates to a bipolar temporary pacing lead which is temporarily used for post-operative myocardial stimulation, including pacing and sensing electrodes, and an affixation coil for lead anchoring as well as an external connector adapted for receiving the proximal end of the temporary lead. Another aspect of the present invention relates to a bipolar permanent nerve lead which is placed adjacent a nerve trunk to be stimulated including bipolar electrodes, an affixation coil, and an insulation flap for preventing unwanted transmission cf electrical energy to surrounding muscle structure.
2. Description of the Prior Art
Temporary heart wires are known in the art, for example, U.S. Pat. Nos. 4,541,440 to Parsonnet and 4,341,226 to Peter Peters (assignee Medtronic), Temporary Lead with Insertion Tool.
Such devices are adapted to be placed in the heart wall by means of a curved needle wherein the electrodes remain within the heart wall and the proximal end of the lead is brought to the exterior of the patient's chest by means of a second straight needle, located at the proximal end of the heart wire.
Devices known in the prior art have drawbacks as their construction is somewhat primitive in that the electrodes constitute merely exposed portions of the conductive wire within the lead, no means is provided for affixing the bipolar electrodes within the heart and dislodgement is a problem, and the lead itself tends to be stiff as it is constructed of two separate wires which lie in a side-by-side configuration causing stiffness in at least one direction of bending.
Also, there remains the problem of providing an external connector for the proximal end of the wire which extends externally from the patient's chest. There is a need for a convenient, easy-to-use, interface, or connector, between the lead per se and the external temporary pulse generator. Such a connector must not require substantial electrical or mechanical manipulations on the part of the surgeon, should be comfortable to the patient, and the electrical contacts must be secure and reliable. Further, the connector should be reasonably economical to manufacture, and, preferably, even disposable.
In regard to nerve wires, these wires in the past were unipolar, were more particularly adapted for implantation near nerve branches, and did not have affixation means. Further, in the prior art, no means was provided for shielding adjacent muscle structure from unwanted stimulation.